玉北区块裂缝型碳酸盐岩油藏复合酸压改造技术

STIMULATING TECHNIQUE OF THE COMPLEX ACID FRACTURING FOR THE FRACTURED CARBONATE OIL RESERVOIRS IN YUBEI BLOCK

玉北区块碳酸盐岩油藏埋藏深、温度高、地层水矿化度高,基质渗透率低、储层裂缝发育,最大破裂压力梯度达26.7 kPa/m,储层改造难度大。开展了碳酸盐岩储层复合酸化压裂改造技术研究,通过优选酸液体系、加砂量和段塞泵注模式,形成了加砂压裂与酸液刻蚀复合工艺、压裂液与酸液交替注入工艺。在玉北区块开展矿场试验并成功应用,对今后塔河外围碳酸盐岩储层改造有一定的指导意义。

The carbonate oil reservoirs in YuBei Block are characterized by deep buried depth, high temperature and formation water salinity, low matrix permeability and well-developed fractures, the maximum breakdown pres- sure reaches 26.7 kPa/m, so the difficulty in the reservoir stimulation is huge. The stimulating technique of com- plex acid fracturing are studied for the reservoirs. By means of optimizing acid solution systems ~ sand input amount and the modes of slug pump injection, the composite technologies between the sandfrac and acid solution etching and the alternating injection technology between the fracturing liquid and acid solution are established. The field tests have been carried out and successfully applied in Yubei Block. All the achievements obtained above possess a certain guiding significances for the future stimulation of the carbonate reservoirs in the outskirts of Tahe Oilfield.